LOADING ...

Has Hubble Detected Rogue Clumps of Dark Matter?

Ryan F. Mandelbaum Jan 14, 2020. 5 comments

Scientists using the Hubble Space Telescope have discovered evidence of small clumps of dark matter warping the light from distant quasars.

Regular matter seems to form only a small part of the universe—much more of the matter seems to be “dark” stuff that influences regular matter via gravity but can’t be detected directly. The most widely accepted theory to explain dark matter suggests that it is a slow-moving particle that can form clumps in the universe. New Hubble observations provide evidence of the smallest clumps yet, which will hopefully further guide scientists’ search for the mysterious material.

For decades, scientists have been aware of various discrepancies between the way they observe objects behaving and the way they predicted those objects to behave, discrepancies that would be fixed with an unobserved source of mass. This has led to a prevailing theory featuring “cold,” or slow-moving, dark matter (versus fast, “warm” dark matter), and various searches using telescopes, particle colliders, and sensitive particle detectors to find the identity of this mass. Cold dark matter should clump together on scales far smaller than a galaxy, but scientists had not found evidence of that clumping—until now.

The search for clumps relies on a concept called gravitational lensing. Mass warps the shape of spacetime itself, so scientists can hunt for mass sources based on how they alter the appearance of distant background light. This warping can cause bright objects like quasars to appear as multiple copies in the night sky. Scientists Leonidas Moustakas and Ben Metcalf in the early 2000s developed a method in which they focused on objects where an intervening galaxy had created a quad, or four images of the background light source (usually a bright, distant object called a quasar). But smaller intervening objects, such as clumps of dark matter, can change the brightnesses of the images. Comparing each of the four images allows researchers to determine whether there are any smaller dark matter haloes, or clumps, in the way.

But past observations had a problem: Other light objects could cause warping, too, and create a signal that mimicked dark matter, called microlensing. Scientist Anna Nierenberg, now at the Jet Propulsion Laboratory at CalTech, realized that quasars release a kind of radiation called “nuclear-narrow line emission” that isn’t affected by microlensing and that Hubble would be able to spot this emission. She and her team submitted a proposal to study these emissions, first in 2014 when she was still a grad student. After a long wait, data acquisition, and analysis on eight of these “quads,” they’ve released their results in a paper in the Monthly Notices of the Royal Astronomical Society.

“It’s a huge validation for me as an early career scientist,” Nierenberg told Gizmodo, who said that at first she was just excited for her proposal to have been selected and that she’d be able to dictate where Hubble should point.

A second paper in the same journal, led by Daniel Gilman at UCLA, argues that the data better agrees with cold dark matter models that include clumping, rather than models without clumping. The smallest clumps that would produce the observed effects would be between 1 million and 10 million times the Sun’s mass, far smaller than a galaxy and perhaps too small to even hold stars. It would just be a big clump of dark matter.

It’s an exciting observation. “Substructure lensing has long been the dream for revealing the nature of dark matter but was held up for almost two decades because of technical issues—for a long time, there were only seven suitable lenses for substructure lensing studies,” Annika Peter, associate professor in physics at the Ohio State University who was not involved in this study, told Gizmodo in an email. “[Gilman’s] paper shows how great constraints on the nature of dark matter can be with this increased sample size.” Basically, the simplest cold dark matter model still works and will be even better-tested with more of these quads.

This is just further evidence of cold dark matter, and scientists are still hunting for what that cold dark matter might be made of. Nierenberg said we’re not at the point where scientists can say for sure that dark matter is a particle that will be found in an experiment on Earth. But this paper serves as gut check that cold dark matter is the right kind of dark matter for scientists to be hunting. Of course, the possibility that dark matter is something completely wild that scientists haven’t thought of yet isn’t off the table. We’ll have to be patient; after all, particle hunts typically take decades .

Researchers will continue to look for these lenses, which will provide further constraints on dark matter’s properties. There’s more Hubble data to sift through, Nierenberg said, and the upcoming Vera Rubin Observatory will be hopefully be able to find more. The search for dark matter continues.

5 Comments

Other Ryan F. Mandelbaum's posts

Why I Went Birdwatching at a Particle Physics Lab Why I Went Birdwatching at a Particle Physics Lab

We drove past the perfect-circle frozen pond delineating the Booster—the second in a sequence of Fermilab’s particle accelerators—and then onto the 2-mile ring road that traces the tunnel that houses the Main Injector accelerator. Along the road are unfrozen ponds filled with water used for cooling research equipment, where Canada geese have taken up residence by the hundreds. We...

Using a DNA-Based 'Computer,' Scientists Get the Square Root of 900 Using a DNA-Based 'Computer,' Scientists Get the Square Root of 900

Using a computer-like system made from engineered DNA, scientists have computed the square root of 900.Biologists have proposed using genetic material for performing computations since as early as 1994. Since then, they’ve found ways to store bits of information in DNA and manipulate those bits via the same rules of logic that computers use. But, according to a recent...

'Remarkable' Mathematical Proof Describes How to Solve Seemingly Impossible Computing Problem 'Remarkable' Mathematical Proof Describes How to Solve Seemingly Impossible Computing Problem

You enter a cave. At the end of a dark corridor, you encounter a pair of sealed chambers. Inside each chamber is an all-knowing wizard. The prophecy says that with these oracles’ help, you can learn the answers to unanswerable problems. But there’s a catch: The oracles don’t always tell the truth. And though they cannot communicate with each...

Scientists Built a Robot From 40 Pigeon Feathers and It Flies Beautifully Scientists Built a Robot From 40 Pigeon Feathers and It Flies Beautifully

Scientists seeking to understand the mechanics of bird flight have constructed PigeonBot, a robot made from 40 pigeon feathers (and a few other components).While airplanes maneuver by altering their wing elements, birds can morph the shape of their entire wings to dive, bank, and coast through the air, increasing both their efficiency and agility. This new study on pigeon wings...

Suggested posts

Behold, Vine Reborn Behold, Vine Reborn

Vine and its sequel, V2, may be dead, but from their ashes arises a new contender to take up the six-second video mantle: Byte.Unveiled in a company Twitter thread Friday, this new app for iOS and Android hopes to be every bit the spiritual successor Vine co-founder Dom Hofmann has been hinting at since 2017. Not in name though,...

DOJ Plans Section 230 Workshop to Host a 'Diversity of Viewpoints' on Internet Speech DOJ Plans Section 230 Workshop to Host a 'Diversity of Viewpoints' on Internet Speech

The U.S. Justice Department is hosting a workshop next month seeking “a wide diversity of viewpoints” on Section 230 of the Communications Decency Act , the federal statute that, with few exceptions, protections major internet companies and private website owners from liability when it comes to the posts and comments generated by users. The Information’s Ashley Gold first reported...

White House Details Exactly How It Plans to Rein In Sales of Fake Crap Online White House Details Exactly How It Plans to Rein In Sales of Fake Crap Online

The Trump administration is adopting a tougher stance to combat the multi-billion dollar market of selling counterfeit goods on online platforms like Amazon, per a Department of Homeland Security report released Friday.Among 11 “immediate actions” outlined, the report calls for a federal committee to help identify the key players in counterfeit networks online as well as additional legislation to...

Google's Having Second Thoughts About Its Dogshit Redesign Google's Having Second Thoughts About Its Dogshit Redesign

Over the years, Google’s become somewhat notorious for killing off its projects, beloved or otherwise. The most recent casualty happened today, with the announcement that the company’s backing off of a controversial search engine update—one that made organic search results and paid-for placements nearly impossible to distinguish.“We’ve heard your feedback about the look,” tweeted Google’s “search liaison,” Danny Sullivan,...

Pentagon Says 34 Troops Treated for Traumatic Brain Injury After Trump Downplays It as 'Headaches' Pentagon Says 34 Troops Treated for Traumatic Brain Injury After Trump Downplays It as 'Headaches'

The White House initially minimized the consequences of retaliatory Iranian missile strikes that hit joint U.S.-Iraqi bases in Iraq on January 8 in response to Donald Trump’s reckless decision to assassinate a senior Iranian official. But last week, news broke that at least 11 U.S. troops had actually been treated for traumatic brain injury (TBI). Pentagon spokesperson Jonathan Hoffman...

YouTube’s Content Moderators Are Asked to Contractually Acknowledge the Job Can Give Them PTSD YouTube’s Content Moderators Are Asked to Contractually Acknowledge the Job Can Give Them PTSD

The contractors charged with keeping YouTube clean from the vilest forms of content that surface on the platform are reportedly being coerced to sign agreements acknowledging that the job could have a severe impact on their mental health, seemingly making any job-related fallout the responsibility of those workers rather than the responsibility of Google or YouTube.The Verge reported Thursday...

Clayton Christensen, Father of 'Disruptive Innovation,' Dies at 67 Clayton Christensen, Father of 'Disruptive Innovation,' Dies at 67

Unless you’re an avid reader of the sort of books CEOs tote around, you may not have heard of Clayton Christensen. You have, however, felt the impact of his work. Christensen, who died at 67 on Thursday due to complications from cancer treatment, is the scholar responsible for coining the term ‘disruptive innovation.’ You know, disruption—the word all your...

You Still Haven't Heard of Quibi, But Don't Worry, Its CEO Apologized for Calling Journalists Pedos You Still Haven't Heard of Quibi, But Don't Worry, Its CEO Apologized for Calling Journalists Pedos

The new streaming service Quibi is facing an uphill battle. Most people don’t know what it is or why it exists. That’s partly because it hasn’t even launched yet, but CEO Meg Whitman recently put it on the map in a less than tasteful fashion when audio leaked of her comparing journalists to pedophiles. She has now apologized for...

Ring Got Reporters to Omit Its Ukraine Staff Is Working on 'Many Other Amazon Projects' Ring Got Reporters to Omit Its Ukraine Staff Is Working on 'Many Other Amazon Projects'

Amazon’s home security company, Ring, pressed the chief editor at a Ukrainian business publication last year to delete a passage in an article touting the successes of Ring’s Kyiv-based research lab, the Intercept reported Friday. The article reportedly included a quote attributed to the general manager of Ring Ukraine stating the lab was not only working on Ring products, but...

A Massive Locust Swarm Poses an 'Unprecedented Threat' to East Africa A Massive Locust Swarm Poses an 'Unprecedented Threat' to East Africa

A grim report from the United Nations warns that unusually large swarms of locusts will be descending upon East Africa in the coming months, in what could be the worst infestation in a quarter century. The pests could pose a serious risk to crops and livelihoods in the region.“The current swarms represent an unprecedented threat to food security and...

Language